There are a number of bugs found by clang dealing with signed quantities that cause the build to fail. These are easy to fix and have already been fixed on the upstream git master, but it would be nice to have the fixes in ports as well.
Fix: Patch attached with submission follows:
How-To-Repeat: cd /usr/ports/emulators/open-vm-tools-nox11
make all CC=clang CXX=clang++ CPP=clang-cpp